The use of high-pressure spray systems for various cleaning tasks is well-known and prevalent in both residential and commercial settings. These systems use either engine-driven or electric-motor-driven pumps to pressurize the water or cleaning fluid for a more powerful and effective spray. Typically the systems use trigger-actuated spray guns or wands that are manipulated by the user to start and stop the flow of high-pressure water from a nozzle or nozzles at the tip of the gun or wand.
In addition to simply spraying water for cleaning purposes, high-pressure spray systems may also be configured to draw a cleaning chemical into the fluid stream for delivery out of the spray gun. The chemical may be introduced forcibly into the fluid stream (i.e., via a separate pump), or it may be drawn into the fluid stream using a venturi placed in-line with the fluid stream, wherein a liquid chemical is fluidly coupled to the throat of the venturi so as to be drawn into the stream under certain pressures. Utilizing a venturi for chemical injection is often the preferred method given the fact that it requires few added components and few modifications to the existing spray system.
In addition to chemical injection, there is often a desire to introduce air into the combined fluid/chemical stream so as to achieve a foaming spray. One common use for such a foaming spray is for a vehicle wash. There have been a number of devices used to achieve this chemical injection with foaming spray on high-pressure spray systems, but each of these devices requires that a separate spray head/nozzle be connected to the spray gun when the user desires a foaming spray. If the user wishes to only use a chemical/fluid combined spray or a fluid-only spray, they must remove the chemical injection and foaming spray device from the gun and replace it with another appropriate nozzle. Such a change-over is cumbersome and time-consuming.
Accordingly, it would be advantageous to provide a chemical injection and foaming spray system for use with a pressure washer that enables the user to switch between a foaming setting, a combined chemical/fluid setting, and a fluid-only setting without removing any components from the spray gun.